DD1 I was certain was a girl. DS I was certain was a boy. With my third child, I KNEW I was having a boy. When the US tech told me it was a girl I almost fell off the table... and told her she was wrong. Uh, no... she was right!! Poor woman, when I argued with her she thought I was disappointed - I couldn't have cared less, I was just certain DD2 was a boy.